1. Technical field
The present invention relates to a side airbag, and more particularly to a side airbag for an automobile, which stably operates by regulating gas flow and time, and a method of folding the side airbag for an automobile.
2. Description of the Prior Art
Generally, an airbag for an automobile is a security system for protecting a driver and passengers when the automobile is collided at its front or side or rolls over.
Such an airbag system may be classified based on its mounting position into a front airbag system mounted on a steering wheel or a dashboard, a side airbag system mounted to a side of a chair to protect people against a side collision of the automobile, a rollover airbag curtain system which operates when the automobile rolls over, and a knee bolster airbag system and a foot airbag system for protecting the knee or the feet. At this time, the airbag is also classified in more detail into a DAB (Driver side Air Bag) and a PAB (Passenger side Air Bag).
Recently, the airbag has a dual-chamber structure so as to minimize the punch-out force transmitted to a user when the cushion is developed.
The dual-chamber structure of the prior art may be found in U.S. Pat. No. 3,799,575 under title the xe2x80x9cProtective device for vehicular passengers incorporating silencing apparatusxe2x80x9d, as shown in FIG. 1.
Such a protective device, recognized as an original technique of applying the dual chamber structure to a side airbag, includes an inner inflatable bag 2 separately mounted in an airbag cushion 1, a screen 8 fixed at an inner side of the inner inflating bag 2 and having a perforated hole, and a storage chamber 3 for discharging compressed and combustible gas or predetermined fluid into a porous area 1xe2x80x2 of the cushion 1 and the inner inflatable bag 2 by combining an explosion-release plug 4 to a manifold conduit 5 having jet port openings 6, 6xe2x80x2, 6xe2x80x3.
This protective device has a regulation function of gas extrusion by collecting heat transferred and fluid flowed according to inflation of the airbag cushion into the screen 8 and the inner inflatable bag 2, and the function of regulating direction of the gas flow injected from the manifold conduit 5 by the screen 8, hereinafter referred to as a gas flow orienting function.
On the other hand, as another example in applying the dual chamber structure to a front airbag, U.S. Pat. No. 5,573,270, discloses an airbag having an inflating gas diffuser with a gas release inflator.
In this patent, it is attempted to seam the inner texture performing the same role as the inflating gas diffuser suitably to an inside of the cushion, and therefore regulating the gas flow of the inflator. The inner texture is comprised of seamed portions and a non-seamed portion, so as to use the gas extrusion regulating function without any perforated hole. In other words, the inner texture makes the gas flowing radially passing through the non-seamed portion between the seamed portions so as to restrain release of the gas.
In the above airbag, because the warp threads and woof of the cushion texture are oriented to same directions as those of the inner texture, the gas may have relatively more smooth linear flow. However, if such a technique is applied to a side airbag having a dual chamber structure for protecting the thorax and the head of a driver, it is very difficult to reconfigure the gas flow.
In this example, the warp thread is a thread in a longitudinal direction (weaving direction) with the texture, and becomes more twisted than the woof. On the other hand, the woof is a thread in a horizontal direction of the texture crossed with the warp thread at a right angle, and it is generally thicker and less twisted than the warp thread. Therefore, the airbag cushion and the inner texture consisting of the warp threads and the woof have fine slit lines in a longitudinal direction (weaving direction), so the gas direct flow is developed to the longitudinal direction.
There is an example of applying the gas flow orienting technique to the side airbag in found U.S. Pat. No. 5,562,506.
As shown in FIGS. 2 and 3, the side airbag 10 includes a cushion 11 having a pocket-like shape in a specific cloth material so that gas may flow inside 11xe2x80x2 thereof for a predetermined time, a section chamber 13 positioned at a side of the cushion 11, and an inflator 12 installed in the section chamber 13 to generate gas from a release hole 15 according to the ignition signal of a sensor controller, not shown, so that the cushion 11 can be inflated to a predetermined size.
In such a configuration, the cushion 11 and the section chamber 13, which are made by folding one texture in a loop, are sewed by multiple lot of seam lines 19a to 19d. The section chamber 13 has a first hole 14 at a side toward the cushion 11 and a second hole 17 at an opposite side. Stud bolts 16 of the inflator 12 are screwed by bolts through the second hole 17 and a third hole 18, formed at an opposite end of the cushion 11 out of the section chamber 13.
An operating method of the side airbag is as follows. If an automobile having the airbag 10 is in a collision, the inflator 12 installed in the section chamber 13 of the cushion 11 is ignited with an ignition signal from the sensor controller not-shown, the gas is released into the inside 11xe2x80x2 of the cushion 11 through the release hole 15 and the first hole 14, and then the cushion 11 is finally developed to protect a side portion of the rider.
FIGS. 4 and 5 are another side airbag 20 of the prior art, disclosed in PCT Publication No. WO 00-20260, which include a cushion 24, in which a lower chamber 22 and an upper chamber 24 are separately formed, and an inflator 26 formed at a lower side of the cushion 24 to supply gas into the lower chamber 22.
The lower chamber 22 has a plurality of discharge holes 27 at an upper side to discharge gas toward the cushion 24. Also, at a lower side of the lower chamber 22, there is provided a flow-changing member 28 in a tube shape wrapping around the inflator 26 for generating gas so as to store the gas therein and move the stored gas to be supplied to a vertical direction.
Seeing operation of the side airbag 20 as constructed above, if there is a collision at a side of the vehicle, a sensing device, not shown, detects the collision and transmits an electric signal to the inflator 26, and the inflator 26 receiving the electric signal then supplies gas by explosion.
The gas supplied from the inflator 26 then changes direction by striking the flow changing member 28, inflating the right side of the lower chamber 22 at first, then flowing upward after inflating the left side, and then passing through the discharge hole 27 of the lower chamber 22 inflating the upper chamber 23.
However, though the protective device for passengers shown in FIG. 1 has a dual chamber structure, in that the inner inflatable bag 2 is mounted in the airbag cushion 1, it is not configured to protect the thorax and the heat at the same time, so it is difficult to effectively and safely protect the passengers.
As for the side airbag 10 shown in FIGS. 2 and 3, because the gas is discharged from the inflator 12 directly to the inside 11xe2x80x2 of the cushion 11, the punch-out force generated when the cushion 11 is developed is directly transmitted to the user, so there is a drawback that it cannot ensure enough safety of the user.
In case of the side airbag 20 shown in FIGS. 4 and 5, because the lower chamber 22 is not uniformly inflated due to the flow-changing member 28 in the lower chamber 22 and at the same time the upper chamber 23 turns around during punching out, that is, generates bag rotation, there are shortcomings that the airbag cannot be developed stably while standing up, the head of the user may slide in contact with the upper chamber 23 unstably, and it is difficult to regulate the speed of the developing upper chamber.
In addition, because the lower chamber of the prior art has a texture which is weaved to one direction, the ratio of gas that escape through the cloth is relatively high. That is, the conventional side airbag has a relatively high permeability, so the pressure in the airbag cannot be maintained for a long time.
Moreover, because the upper chamber is inflated after the lower chamber, there may be too much interaction between the upper and lower chambers and therefore there is high probability of unstable development.
The present invention is designed to overcome such drawbacks and shortcomings of the prior art, and an object of the present invention is to provide a side airbag for an automobile and its folding method, in which a cushion may be developed with in a set time without the eccentricity, and effectively protect a driver and passengers in the vehicle.
Another object of the present invention is to provide a side airbag for an automobile and its folding method, which may stably develop a second chamber by folding the second chamber to be inwardly depressed and then folding it compactly.
Still another object of the present invention is to provide a side airbag for an automobile and its folding method, in which gas is supplied inside a center chamber formed in a tube-type tether, and the gas of the center chamber flows in the first and second chamber positioned above and below the center chamber, so that the cushion may be stably developed without being twisted.
In order to accomplish the above object, the present invention provides a side airbag for an automobile installed to the side of a chair back of an automobile and having an inflator, which supplies gas by explosion upon receiving a signal through an electric wire when the automobile crashes, in which the side airbag includes a first airbag module including first and second cushion pads having extensions with a plurality of insert holes on one side and combined each other to form a second chamber for filling gas therein, and an inner cushion pad, which is folded in a half size to form a first chamber between the first and second cushion pads and has a plurality of first gas exhaust holes formed upward thereon and an inflator-mounting portion which is added to the extensions; and an inflator module including a fixing member having first and second mounting holes into which both sides of the inflator are inserted, the fixing member fixing the first airbag module to an inside of the side of the chair back by inserting outwardly protruded screws thereof into the insert holes of the first and second cushion pads and into an insert hole of the inner cushion pad.
In order to obtain the above object of the present invention, the present invention further provides a method of folding a side airbag for an automobile, which includes the steps of folding ends of first and second pads, positioned at an opposite side to an inner cushion pad, to a position near a cushion seam line; folding right portions of the first and second folded cushion pads to the left so that an upper side of an inflator-mounting portion becomes perpendicular to the right side of the right portion; folding left portions of the first and second folded cushion pads to the right to be partially overlap with the right portion so that the upper side of the inflator-mounting portion becomes perpendicular to a left side of the left portion; folding lower portions of the first and second cushion pads upward so that a lower side of the lower portion becomes substantially parallel to the upper side of the inflator-mounting portion, so making the first airbag module folded in a rectangular shape; and partitioning the first airbag module into three sections to be folded so that the first airbag module has a size identical to a finally folded section.
In order to perform the above object of the present invention, there is also provided a side airbag for an automobile installed to the side of a chair back of the automobile having an inflator which supplies gas by explosion up on receiving signal through an electric wire when the automobile crashes, in which the side airbag includes a second airbag module, which also includes third cushion pads for forming a first chamber, to an inflator-mounting portion of which reinforcing pads are attached along a seam line for heat-blocking and structural reinforcement, the third cushion pads having a tear seam at the center thereof, and a fourth cushion pad to form a second chamber by seaming both ends to combine the lines marked at a center of the third cushion pad and then seaming an outer seam line, wherein the second airbag module is folded by folding the fourth cushion pad in advance to be arranged in the first chamber, and then piling the third cushion pad and seaming the third cushion pad along seam lines so that the inflator-mounting portion is opened.
In order to achieve the above object, the present invention also further provides a side airbag for an automobile installed to a side of a chair back of the automobile and having an inflator which supplies by explosion gas on the receipt of a signal through an electric wire when the automobile crashes, which side airbag includes a third airbag module, which also includes fifth and sixth cushion pads having lateral tether-attaching portions at inner centers thereof; and a tube-type tether seamed at the tether-attaching portions to form a center chamber, wherein the tube-type tether forms a plurality of gas exhaust holes and a passage so that the third airbag module supplies from a center thereof to a lower first chamber and an upper second chamber, respectively.